Joe Ricketts, the billionaire founder of TD Ameritrade and a major Republican donor, has become embroiled in a firestorm over a series of emails containing racist jokes and anti-Muslim conspiracy theories.

Nebraska Gov. Pete Ricketts, one of Joe Ricketts’ sons; the Chicago Cubs, which are owned by the Ricketts family; and TD Ameritrade all tried to limit the fallout Tuesday from the emails tied to the elder Ricketts.

Joe Ricketts, 77, issued a statement apologizing for the emails after they were posted online Monday.

“I deeply regret and apologize for some of the exchanges I had in my emails,” Joe Ricketts said in a statement on his website. “Sometimes I received emails that I should have condemned. Other times I’ve said things that don’t reflect my value system. I strongly believe that bigoted ideas are wrong.”

The emails, which were posted on the website Splinter News, include several expressing anti-Muslim sentiments. In one, Joe Ricketts said, “Muslims are naturally my (our) enemy.” He asked his assistant to save another, which described a supposed Muslim plan for taking over the country. Others detailed conspiracy theories about former President Barack Obama’s faith and life.

Some have racist content, including an April 2011 email in which Ricketts responded “great laugh” regarding a forwarded joke with a punchline that includes the word n—–. He responded “I like this” to another forwarded message that complains about special days for certain groups, including Yom Hashoah, or Holocaust Remembrance Day, and Martin Luther King Day.

The email exchanges were from 2009 through 2013. The Splinter News story did not say how the emails were obtained.

Gov. Ricketts issued a statement Tuesday that echoed his father’s: “My father said he deeply regrets and apologizes for some of the exchanges in his emails. He admitted that he has said things that don’t reflect his value system and that he strongly believes that bigoted ideas are wrong.”

“I also believe bigoted ideas are wrong,” the governor added. “The language and views expressed in those emails do not in any way reflect my views and are not appropriate.”

Gov. Ricketts was not a party to most of the emails. But in a 2010 exchange, he questioned the reliability of the emails being sent by his father. Joe Ricketts had sent son Pete an email chain titled “Americans believe in religious freedom — Muslims don’t.”

Gov. Ricketts responded: “Dad, I recommend you go to www.snopes.com and search on these stories before you pass them on. In this case, there is a dispute over what exactly happened.”

Joe Ricketts emailed back, calling Islam “a cult and not a religion.”

Son Pete again urged his father to look at the fact-checking website. “I am not sure that your statement is accurate with regards to Islam but I recommend reading the piece on snopes,” Gov. Ricketts wrote in an email.

In an interview, Nebraska Democratic Party Chairwoman Jane Kleeb sought to tie Joe Ricketts’ statements to the governor.

Kleeb speculated that the younger Ricketts will attempt a Senate run in 2020, though he has denied speculation that he wants to do so.

“For voters in Nebraska, the type of hate-filled messages coming from the Ricketts family and the fact that they continue to use their money to push right-wing conservative agendas should be alarming and disqualifying for Pete Ricketts,” she said.

State Sen. Ernie Chambers of Omaha, who has clashed with Gov. Ricketts on a number of issues, including the death penalty, read a news account of the controversy on the floor of the Nebraska Legislature on Tuesday morning.

He called both Joe Ricketts and the governor “racist” and said it appeared Joe Ricketts was only sorry because “he got caught.”

“He spoke what was inside of him. No one put a gun to him,” the senator said. “And his son lives his racist values.”

In Chicago, a trio of Islamic groups held a press conference Tuesday to condemn the emails. Ahmed Rehab, executive director of the Chicago office of the Council on American-Islamic Relations, called them “alarming and highly disappointing.” The chairman of the Council of Islamic Organizations of Greater Chicago, Irshad Khan, described them as “cruel and repugnant.”

“Such discourse has no place in American society,” he said.

Representatives of TD Ameritrade and the Cubs both sought to distance their organizations from Joe Ricketts.

Cubs’ Chairman Tom Ricketts issued a statement saying his father’s emails don’t reflect the values of the Cubs and highlighting that his father isn’t involved in the Cubs’ operations.

Joe Ricketts helped his children buy the Chicago Cubs in 2009. He sold 34 million shares of TD Ameritrade to make the purchase.

“We are aware of the racially insensitive emails in my father’s account that were published by an online media outlet. Let me be clear: The language and views expressed in those emails have no place in our society,” Tom Ricketts said. “These emails do not reflect the culture we’ve worked so hard to build at the Chicago Cubs since 2009.”

TD Ameritrade spokeswoman Becky Niiya said Joe Ricketts stepped down as chief executive officer in 2001 and retired from the board in 2011.

“The exchanges disclosed yesterday reflect points of view that run counter to our values and what we stand for at TD Ameritrade: namely diversity, inclusion and compassion for each other,” she said. “People matter — all people — and it’s our diversity as a company, a country and a society that makes us strong.”

Joe Ricketts lives near Jackson Hole, Wyoming, rather than in his native Nebraska, because Wyoming has no income tax. He has spent millions promoting conservative political candidates and causes.

Four years ago, he donated $100,000 to the successful effort to reinstate Nebraska’s death penalty, which was also financially supported by Gov. Ricketts.

In 2016, he and his wife, Marlene, donated nearly $6 million to Our Principles PAC, a group that fought against Donald Trump in several presidential primary states.

Trump famously responded on Twitter. “I hear the Ricketts family, who own the Chicago Cubs, are secretly spending $’s against me. They better be careful, they have a lot to hide!”

Once Trump won the nomination, the couple threw their support behind him. A spokesman said they were “proud to support Trump and Pence and other Republican leaders who will push for conservative policy solutions.”

The Rickettses are the principal donors behind the ESA Fund, formerly the Ending Spending Action Fund, which has poured millions into defeating and supporting congressional candidates. In 2014, the ESA Fund spent $22 million, of which $16 million was spent opposing Democratic candidates.

Joe Ricketts also established the Cloisters on the Platte, a multimillion-dollar religious retreat center south of Gretna that opened last year.

He founded other charities as well, including the Opportunity Education Foundation, the Ricketts Conservation Foundation and The Ricketts Art Foundation.

In one email, Ricketts mentioned his education foundation and its support of schools in Africa. Those include one he described as a Muslim school in Uganda. The email starts, “Yesterday I was quite hard on Muslims in our conversation so I wanted to send you this information.” He went on to say that he liked helping Muslim schools “to show them that we are not bad people.”

World-Herald staff writers Paul Hammel and Roseann Moring contributed to this report, which includes material from the Associated Press.